Syringe with passive safety lock

ABSTRACT

A syringe designed with a passive safety locking means to effectively and reliably disallow unintentional displacement of the plunger toward the distal end if the syringe. The safety locking means is designed to affect reliable automatic release on at least two (2) points of engagement of the syringe for its intended use namely the controlled dispensement of generally viscous substances therein.

BACKGROUND

The invention here disclosed relates primarily to syringes and in particular those typically used for medical purposes that allow unintended dispensement of fluid substances from the syringes main staging chamber.

The main purpose of the improvement here disclosed is to provide a reliable, safe, simple and low cost method of passively and automatically locking a syringe from unintended dispensement of its contents when and only when not engaged for its ultimate purpose and allowing for automatic unlocking whenever and however many times a syringe is engaged for its ultimate purpose upon at least two points of contact.

Various attempts to create syringe locks have been made such as the locking mechanism disclosed by Watts (20070049872-A1 US). These attempts allow effective locking control by way of the deliberative action of the user to engage the locking mechanism. Further, the locking mechanism is disclosed as a separate part which will lead to inconsistent use where safety is a factor.

The invention here disclosed provides passive locking control of the syringe plunger in its preferred embodiments. Further, the preferred embodiments accomplish the said passive locking control within a simple low cost and easy to manufacture and implement structure.

Passive locking control is necessary to ensure maximum effective use, application safety enhancement and reduced waste including that of sometimes expensive medical supplies.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional side view of a preferred embodiment of a syringe cylinder, casing and the attached locking slip collar in its post injection mold manufacture position.

FIG. 2 is a top view of the syringe cylinder and casing depicted in FIG. 1.

FIG. 3 is a cross sectional side view of the syringe cylinder and casing depicted in FIG. 1 with the locking slip collar depicted in locked working engagement with the open cylinder end and its corresponding wedge seat.

FIG. 4 is a side view of the syringe cylinder and casing depicted in FIG. 3 with the plunger assembly installed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As illustrated by FIGS. 1,2 & 5, the syringe cylinder-case, FIG. ______, is molded with a locking slip collar ______ attached in a manner to allow purposeful concentric engagement with the open end of the syringe cylinder-case ______ after the plastic molding process is complete as illustrated in FIG. 2.

As illustrated in FIG. 2 once the locking slip collar ______ is rotated and locked into its final working position the attaching flexible plastic strip acts both as a hinge and spring in order to bias the locking slip collar in the preferred opposite direction away from the syringe cylinder-case's open end ______.

As illustrated in FIG. 3 a plunger arrangement ______ is inserted into and past the locking slip collar ______ and into the cylinder-case simultaneously. The locking slip collar ______ is designed with a slight interference around the plunger's concentrically round tube base ______. As the plunger arrangement ______ is displaced toward the distal end of the cylinder-case ______ the locking slip collar ______ is driven into a wedge seat arrangement designed within the open end of the cylinder-case ______ designed to engage a corresponding wedge seat as part of the locking slip collar ______. The engagement of the said wedge seat arrangement exponentially increases resistance between the locking slip collar ______ and the plunger's concentrically round tube base ______ which ultimately locks the said plunger arrangement and disallows further unintentional displacement of the plunger arrangement therein ______ towards the distal end of the cylinder-case ______ which prevents unintentional dispensement of the contents therein.

As illustrated in FIGS. 2+3 once the locking slip collar ______ is rotated into its final working position engagement of the syringe arrangement for its intended purpose automatically and reliably displaces the locking slip collar ______ in the opposite direction of the displacement of the plunger arrangement ______ and the wedge seat arrangement ______ which facilitates disengagement of the locking slip collar allowing low resistance displacement of the plunger arrangement ______ towards the distal end of the cylinder-case end to a selectively desired displacement.

As illustrated in FIGS. ______+______ the locking slip collar ______ can be manually rotated clockwise engaging thread tabs as part of the syringe cylinder ______ that effectively drive and lock the locking slip collar linearly into its fully engaged position restricting free displacement of the plunger assembly ______. Rotating the locking slip collar counter clockwise past the neutral default-passive position engages thread tabs ______ that effectively drive and lock the locking slip collar linearly in its fully disengaged position allowing free displacement of the plunger assembly ______.

In the preferred embodiment the plunger ______ includes a simple one way locking lip ______ at it's distil end which allows the plunger ______ to pass through the locking slip collar ______ and allows a full range of dual direction slidable connection with the locking slip collar ______ but disallows reverse direction disengagement of the plunger passed the locking lip ______ in order to discourage disengagement of the primary purpose passive safety feature as may be desired. 

1. A syringe assembly comprising: a. a syringe cylinder means including a reduced orifice distal end configured to allow fluid communication to a hollow needle means and an open end configured to allow a manually engaged plunger arrangement allowing sealed slidable engagement within the syringe cylinder means, b. a manually engagable plunger means configured to allow sealed slidable engagement within the syringe cylinder means, and c. a passive plunger locking means to allow effective automatic retention of the said manually engagable plunger means within the syringe cylinder means in order to disallow unintentional longitudinal displacement of the said plunger means within the said syringe cylinder means toward the said distal end of the said syringe cylinder means.
 2. The syringe assembly in claim 1 including a manual means to disengage the said passive plunger retention means allowing intentional longitudinal displacement of said plunger means within the said syringe cylinder means toward the said distal end.
 3. The syringe assembly in claims 1 and 2 including an automatic passive means to disengage the said plunger means from said automatic locked retention when said syringe assembly is manually engaged for its primary purpose.
 4. The syringe assembly in claims 1, 2 and 3 including: a. a locking slip collar means configured to allow the said plunger means to pass through its center and allow low resistance longitudinal movement of said plunger means therein, b. a wedge seat means configured upon the outer periphery of the said locking slip collar means, c. a corresponding wedge seat means configured within the said syringe cylinder means open end to allow effective concentric wedge seat mating with the said locking slip collar's said wedge seat means and effectively constrain linear displacement of the said plunger means within the said syringe cylinder means.
 5. The syringe assembly in claim 4 including a flange means configured upon the said locking slip collar means to allow effective engagement of the said locking slip collar means by manual means to disengage said wedge seat mating and allow free longitudinal displacement of the said plunger means within the said syringe cylinder means toward its distal end.
 6. The syringe assembly in claims 4 and 5 including at least one finger pad means configured in conjunction with said slip collar flange means to allow effective manual or passive engagement of said wedge seat to affect reliable point of use disengagement means allowing free longitudinal movement of said plunger means.
 7. The syringe assembly in claim 6 including a syringe cylinder flange means configured outboard of the said syringe cylinder means at or near its said open end including: a. a means to allow said locking slip collar finger pad means to be installed within and pass through the said syringe cylinder flange means whereby said finger pad means are effectively and passively engagable after marriage with said cylinder flange means when the operative syringe assembly is engaged for its intended purpose.
 8. The syringe assembly in claims 4, 5, 6 and 7 including a means to effectively lock the said slip collar means in concentric alignment and engagement with the said syringe cylinder's open end and effectively limit the linear movement of the said slip collar means to a predetermined distance in order to adequately allow engagement and disengagement of the said slip collar wedge seat means with the said corresponding syringe cylinder's open end wedge seat means.
 9. The syringe assembly in claims 4, 5, 6, 7 and 8 including a manually releasable locking means configured to selectively lock the said locking slip collar wedge seat means in effective mated engagement with the said syringe cylinder's corresponding wedge seat means and effectively constrain linear displacement of said plunger means.
 10. The syringe assembly in claims 4, 5, 6, 7, 8 and 9 including a manually releasable unlocking means configured to selectively lock the said locking slip collar's wedge seat means in effective unmated engagement with the said syringe cylinder's corresponding wedge seat means effectively allowing free linear displacement of the said plunger means.
 11. The syringe assembly in claims 4, 5, 6, 7, 8, 9 and 10 including a one way locking means which allows the plunger means to pass through the locking slip collar and allows a full range of dual direction slidable connection with the locking slip collar but disallows reverse direction disengagement of the plunger from the locking slip collar means in order to discourage disengagement of the primary purpose passive safety feature. 